Finding inspiration in the conservatory

If you've been to the Maryland Zoo in Baltimore, you've probably seen the Howard Peters Rawlings Conservatory — that big glass building with a curvilinear roof and cupola. So has Alan Stein.

Stein, the director of architecture, founder and president of Denton-based Tanglewood Conservatories, has visited the Rawlings Conservatory many times and recently drew on the structure for inspiration while designing a conservatory for a client in Northern Virginia.

Also known as sunrooms, glass houses, palm houses, winter gardens, orangeries and other clever, yet obscure, names, these heated glass rooms a can be free-standing or attached to the sunny side of a house.

Certainly nothing new on the residential architecture scene, the conservatory as we know it dates back to 17th-century Europe and maintains popularity as the ubiquitous sunroom to this day. While the glazing (glass meets frame) technology has certainly advanced, the allure of conservatories is often that they recall a bygone era.

Reaching their height of prominence in the 19th century, it seems that glass houses stocked with exotic and tropical plants acquired from far-off lands were requisite to maintaining one's image as a trend-setting land baron of the time.

Such orangeries or winter gardens were often large, ornate glass structures that functioned as much for keeping tropical plants as for entertaining guests.

Today, a functional greenhouse for overwintering tropical plants can be built from a mail-order kit, but more often people are adding glass rooms for other purposes sometimes not unlike those of the 18th- and 19th-century landed gentry — a place to entertain, to connect with nature, to bask in sunlight no matter what the thermometer says.

Using state-of-the-art technology and engineering, Tanglewood Conservatories produces some of the finest conservatories available, with work that includes $15,000 glass roofs and 5,000-square-foot swimming pool enclosures.

Stein started Tanglewood in 1993 with wife, Nancy Virts, but was trained as an architect and started a design-build company. As it turns out, early on, he found himself faced with the challenge of building conservatories.

"One of my clients wanted me to build an English conservatory, and then another client soon asked for a conservatory," says Stein. "We realized there was a market — other products were imported from England and weren't made with American housing in mind, so we launched Tanglewood."

In the past 18 years, the company has worked on residential and commercial conservatory projects all over the world, including Hawaii, New York, China, Eastern Europe, Africa, Australia, Saudi Arabia and Turkey

And while Tanglewood's projects grace houses in and around the Baltimore region, Stein has designed only one using one of Baltimore's most recognizable structures as a model. Completed in 1888, Baltimore's Rawlings Conservatory in Druid Hill Park was designed by George Aloysius Frederick, who at the age of 19 was hired by the Baltimore Parks Commission to design buildings and pavilions. This "Palm House," as Conservatory Supervisor Kate Blom refers to it, was, like most American conservatories, inspired by European antecedents.

"I don't have any concrete data on what inspired the design of the Palm House," says Blom, "but if one were to look at Kew's Palm House [in the Royal Botanic Gardens outside of London], remove the side elevations and add a cupola on top, you would have a structure that strongly resembles the Palm House in Baltimore."

Completed in 1848, the Kew Palm House, then, was a possible inspiration for the Druid Hill Park Palm House 40 years later, which in turn inspired Stein more than a century later.

While the Kew Palm House and the Rawlings Conservatory were, according to Blom, both "created specifically to house exotic palms in an unobstructed space," Tanglewood's smaller version was, like most modern residential conservatories or sunrooms, designed as additional living space.

What's common among all three is the design. Blom credits Kew as "a very innovative project and the first where wrought iron was used to span wide widths. The inspiration and engineering for this construction came from the ship-building industry … essentially a design of upturned hulls."

Picking up, it is assumed, on this feat of engineering, the Rawlings design "looks very industrial, using steel web trusses," Stein says.

That look, as it happens, is exactly what his clients were after. "They really liked the idea of that industrial steel look on the interior," says Stein. "This was a great opportunity to replicate that but using modern technology."

Stein's design, albeit smaller, mimicked the basic shape of the Rawlings Conservatory, which, he says, "is basically a modified square ... with the corners rounded off, a curving lower roof and an ornate cupola on top."

The real genius of the Rawlings design, however, can be seen in the relative daintiness of the structural elements. "There is a real transparency to the design," says Stein. "You ask, 'What holds this thing up?' It is like a big soap bubble. We had to really study how the steel was used to create the appearance of minimal framework and lots of transparency."

With early conservatories, heat was essential to the success of housing collections of tropical plants. Both the Kew and Rawlings structures were designed with massive boilers to keep the interior space warm through winter.

Modern-day residential conservatories benefit from current technologies and are typically built to transition seamlessly from the rest of a home's interior. The spaces, light-filled as they may be, are well-insulated, heated and air-conditioned, creating a comfortable living space as well as a showplace for plants.

What has remained a constant over the centuries is that whimsical, magical limbo conservatories have the power to create. A segue to the landscape, an open ceiling to the sky, conservatories seem neither indoors or out.